SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f71217095b87559541ad4df1532e89b835e35ca7e0ceb65e8b06a64f0694de6' 
  AND token = 'UuKDoqMhTy6UcK0xP8S5vwjVxl23ZMB4Mrh7ZLnvS/I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}